Thousands of people who gamble online are voters and if internet gambling is banned then votes will be lossed and they don't want that, come next election!
I've been surprised by how strong the poker sites have become and can only see more rapid growth there.
Otherwise I believe applications for PDA's and other portables will enable both casino gambling and sports betting while on the move e.g. while commuting. This style of gambling will have more impact in Europe and parts of Asia than in the US.